All the I2C hardware is using the same hardware I2C port on the esp32.

The ESP32 works using the Blynk Platform and it displays the data on ST7735 using the UCGLIB.
The IO pins are extended using the I2c MCP23017 giving the chance to add enough buttons. It uses the Adafruit Library: https://github.com/adafruit/Adafruit-MCP23017-Arduino-Library
The offline time kept by an external I2C RTC DS13017z using a library that does not conflict with the Online RTC used by Blynk: https://github.com/Seeed-Studio/RTC_DS1307